[s-cars] Window condensation?

[Thomas R Green]

Chris,

You must have restricted airflow somewhere or moisture being  
introduced into
the car via the air system.  When the a/c operates (above 37F) it may  
not be
noticed since a/c dries the air.   The cold air is low in humidity and  
the heat
will further reduce the relative humidity unless some moisture is  
introduced.
If it contains coolant from the heater core, the smell should be  
noticed, and the
film should form on the windshield first.

Take Brett's advice and investigate the plenum area for the problem.   
It should
receive regular attention to keep it clean.  There is also a provision  
for a
cabin filter at the back of the a/c expansion coil box.  It is not too  
convenient
to access;  the wiper arms and trim piece must be removed to get to  
the cover.
The filter was not included when the car was delivered but a previous  
owner
may have installed one.  Even if it is not there, that area will  
collect junk from
the plenum and kleenex tissue and other things from the glove box when  
in
the recirc mode.  (That's the recirc flap you referred to;  it closes  
when using
fresh air and opens when the exterior door at the filter box closes  
for recirc
air.  The coils and box should be dry since the a/c has not been  
operating
and easier to clean out.

I assume you would have already said the air didn't go to the  
windshield on
defrost or to your feet on heat if that was the case, but I am  
including this link
for the climate control system troubleshooting for information.

http://www.12v.org/maintenance/index.php?section=tr&ss=hvac

Tom

Brett:  The S6 rear vents are in the C-pillars covered by a plate  
where it meets
the quarter panel, and are trouble-free IME.

> -----Original Message-----
> Date: Mon, 8 Feb 2010 18:07:40 -0500
> From: Brett Dikeman <brett.dikeman at gmail.com>
> Subject: Re: [s-cars] Window condensation?
> To: "Hemberger, Chris J PW" <chris.hemberger at pw.utc.com>
> Cc: s-car-list at audifans.com
> Message-ID:
> 	<9d9c4a331002081507rec156d4u4782574094de7efb at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> On Mon, Feb 8, 2010 at 2:42 PM, Hemberger, Chris J        PW
> <chris.hemberger at pw.utc.com> wrote:
>
>> Anyone have any experience and/or suggested repair to address  
>> interior
>> window condensation during cold, dry weather as we're getting here in
>> N.England??
>> ?Had a similar problem on my '91 Type 44 200q and the repair
>> was simply to replace a broken spring controlling the fresh-air flap.
>> Looked at my 95 S6 and the configuration looks different - any
>> suggestions?
>
> Have you checked the position of the flap that controls air inlet when
> set to a temperature that matches the interior, versus one that is
> wildly off and would trigger the flap closing?
>
> Also, have you checked for leaves/debris, and clear drains, behind the
> firewall and under the cover?  The leaves/dirt retain moisture, and a
> clogged drain will let water stick around.  Lots of leaves will hinder
> airflow.  Someone on the 200q20v list had a similar problem and found
> that his condenser was covered in junk, restricting airflow into the
> car.
>
> I wonder if the rear vents under the back bumper (assuming the C4 has
> them) ever stick and cause this sort of problem...probably not.
>
> -B